Photodynamic antimicrobial therapy (PACT) involves the utilisation of photosensitizers activated by exposure to visible light in order to eradicate microbes. Photodynamic effect of the particular photosensitive substance (PS) is attributed to its ability to penetrate susceptible microorganisms, to absorb the light of certain wavelength, and to generate reactive cytotoxic oxygen products.The target microorganisms for photoinactivation are bacteria, fungi, viruses and protozoa.
Photodynamic antimicrobial therapy is proposed as a potentially topical, non-invasive approach suitable for treatment of locally occurring infection. The fact that bacteria are becoming increasingly resistant to antibiotics and antiseptics has lead to an increased interest in the development of new alternative eradication methods, such as PACT.
Research and development of photosensitive substances are aimed at finding effective antimicrobial substances, which would have a broad-spectrum potency.